4-MI: The Dark Side Of Coke

Do you like the delicious, sparkling, black coke that is served in almost every restaurant worldwide? No matter which company produced the coke that you drink, it is always coloured black, isn’t it? But what is this dark colorant really made of? Have you ever thought about this? Apart from having too much sugar and phosphoric acid in there, there is evidence of additional frightening stuff in the drink: a chemical named 4-methylimidazol(4MI), which brings the black color but which is also thought to be cancerogenic.

This chemical is used in many different industry sectors, e.g. in production of pharmaceuticals, pigments, cleaning chemicals, agricultural chemicals and rubber. But 4-MI is also a by-product of the food industry. It is part of tobacco smoke as well as part of the colorants E150 a-d. E150d is the chemical that is used to color (German) coke into black.

The Effects of 4-MI on the Body

In a scientific study published by Chan et al. in 2008 the toxicity of 4-MI was investigated in rats and mice. 50 rats (both female and male) and 50 mice (both female and male) received different 4-MI conentrations with food over a period of 106 days. Survival rates were evaluated against control grops that did not receive any 4-MI and overal physical constitution of the animals was assessed during the test period.

Survival rates of rats and mice were equal in both groups. At highest doses, body weight of 4-MI rats decreased significantly compared to the control group. Additionally, particularly female rats in the 4-MI group suffered from increased agitation, increased activity, impaired movement, seizure and leukemia. Both male and female rats in the 4-MI group developed hepatic histiocytosis and chronic inflammation.

As per the rats, survival rates in 4-MI mice were similar to the control group. However, in male and female 4-MI mice scientists observed significant clustering of pulmonary tumors.

These results led to the assumption that 4-MI induces lung tumors in mice and leukemia in rats and thus is considered cancerogenic.

The Reaction of the Coke Industry

Following the results of this study, the US state California included 4-MI into its list of cancerogenic substances. Because this could have led to obligations of warning signals on coke bottles, the coke industry decided to change the manufacturing protocol of the colorant E150d in a way that 4-MI concentrations stay below the critical limit, which means no labelling on bottles is required. What needs to be considered in this regard is that many people in the world drink huge amounts of coke every day. So even if the 4-MI concentration is below the critical limit for “recommended daily intake” (the word recommended is really weired when we talk about coke, isn’t it?), it can still go above the cut-off in people drinking way more.

Interestingly, the American coke industry tried to use the study by Chan et al. to prove exactly the opposite. They claimed that female 4-MI rats developed decreased amounts of tumors in sexual organs, while male 4-MI rats developed decreased amounds in the adrenal medulla. Wha they didn’t tell is that these observations were discussed as a result of the intense weight loss rather than as a direct effect of 4-MI.

What is even worse is that the US Food and Drug Association (FDA) claims that 4-MI is harmless, although the cited study proves the opposite.

So, what shall we do with this information? In my opinion, it is the responsibility of each individual to evaluate the risk such chemicals bring to their lives. I, myself, said Goodbye to coke and other artificial lemonades a long time ago.